1. Field of the Invention
The present invention relates to a weight training barbell, more particularly to a barbell which vibrates thereby reducing the time needed to train and the tendency to develop a cramp with little stress to the body.
2. Description of the Related Art
Conventional barbells comprising a tube-shaped barbell bar and weights placed on its ends are well known and widely used. Barbells of the aforementioned type serve to train the muscles, especially the musculus biceps brachii (bicipital arm muscle) and the musculus triceps brachii (tricipital arm muscle). Training sequences with conventional barbells place high requirements on the endurance of the person doing the training, because measurable success is achieved only after a relatively long period of training. Furthermore, during the exercises, problems caused by the rough and fine coordination of the movement sequences can develop over time.
A barbell with a tube-shaped bar that carries weights at its ends is described in German patent publication DE 36 09 363 C2. At each end the weights are located within enlarged hollow tips. The hollow space is larger than the weight located therein. As a result, when the direction of movement of the barbell is reversed, the deceleration of the inert masses does not occur until after the weight has moved through the empty space and arrived at the limiting wall of the space that faces away from the direction of movement. Consequently, the muscles and wrist of the person training experience an unexpected impetus at this time, caused by the deceleration of the inert masses, thereby placing great stress on the muscles and wrist.
Another barbell with a tube-shaped bar with disc-shaped weights attached to its ends is described in U.S. Pat. No. 3,617,056. The weights are located on a shaft that runs through the bar of the barbell and is mounted therein so that the weights can rotate. The weights connected to one another in this way can be placed into rapid rotation. When the weights are placed in rapid rotation, the barbell opposes the rotation of the rotational axis with high resistance. However, a sudden change in the direction of movement can result in nutational or precessional motions.
It is desirable to develop a muscle training device which is capable of efficiently achieving muscle development without causing undue stress to the body of the person training.